1. Which of the following is NOT a function of the cardiovascular system?

A. Transporting oxygen to cells
B. Maintaining blood pressure
C. Carrying waste products to the kidneys for removal
D. Initiating the immune response

Correct answer: D

Rationale: The cardiovascular system is responsible for transporting oxygen to cells (option A), maintaining blood pressure (option B), and carrying waste products to the kidneys for removal (option C). However, initiating the immune response (option D) is not a function of the cardiovascular system. The immune response is primarily carried out by the immune system, which includes organs like the spleen and lymph nodes. While the cardiovascular system does play a role in immune function by transporting immune cells and antibodies, it is not responsible for initiating the immune response. Therefore, option D is the correct answer.

2. Which element is used in fluorescent lamps and emits ultraviolet light when excited?

A. Mercury
B. Neon
C. Argon
D. Krypton

Correct answer: A

Rationale: Mercury vapor in fluorescent lamps generates UV light that excites phosphors on the lamp's inner surface, producing visible light.

3. Sweat glands help regulate body temperature by:

A. Producing sebum for lubrication
B. Constricting blood vessels in the skin (sweating doesn't cause constriction)
C. Releasing a watery fluid that evaporates for cooling
D. Thickening the epidermis for insulation

Correct answer: C

Rationale: The correct answer is C. Sweat glands help regulate body temperature by releasing a watery fluid that evaporates for cooling. When the body temperature rises, sweat glands produce sweat, which is mostly composed of water and salts. As this sweat evaporates from the skin's surface, it absorbs heat energy from the body, thus cooling it down. This process is essential for maintaining a stable body temperature during physical exertion or exposure to heat. Options A, B, and D are incorrect as sebum produced by sebaceous glands lubricates the skin, blood vessels dilate rather than constrict during sweating to release heat, and the epidermis does not thicken for insulation related to sweat glands.

4. What is the primary function of the myelin sheath that surrounds some axons in the nervous system?

A. To initiate nerve impulses
B. To transmit sensory information
C. To speed up the transmission of nerve impulses
D. To connect neurons at synapses

Correct answer: c

Rationale: The primary function of the myelin sheath that surrounds some axons in the nervous system is to speed up the transmission of nerve impulses. The myelin sheath acts as an insulating layer, which helps nerve impulses travel faster along the axon by allowing them to 'jump' from one node of Ranvier to the next, a process known as saltatory conduction. This increases the efficiency and speed of signal transmission, enabling rapid communication within the nervous system. Therefore, option C is the correct answer as it accurately describes the role of the myelin sheath in enhancing the speed of nerve impulse transmission.

5. What is the acceleration of an object moving at a constant speed of 20 m/s if it comes to a complete stop within 5 seconds?

A. 0 m/sÂ² (no acceleration)
B. 4 m/sÂ²
C. -4 m/sÂ²
D. Information insufficient

Correct answer: C

Rationale: The acceleration can be calculated using the formula: acceleration = (final velocity - initial velocity) / time. In this case, the final velocity is 0 m/s (as the object comes to a complete stop), the initial velocity is 20 m/s, and the time taken is 5 seconds. Plugging these values into the formula, we get acceleration = (0 m/s - 20 m/s) / 5 s = -20 m/s / 5 s = -4 m/sÂ². Therefore, the acceleration is -4 m/sÂ².

6. Which element has the lowest electronegativity value?

A. Oxygen
B. Fluorine
C. Helium
D. Chlorine

Correct answer: C

Rationale: Electronegativity is the tendency of an atom to attract electrons towards itself in a bond. Noble gases like helium have very low electronegativity because their outer electron shell is already full and stable.